Dispersion for hot rolling aluminum products

ABSTRACT

THIS INVENTION RELATES TO AN OIL-IN-WATER DISPERSION FOR THE HOT ROLLING OF ALUMINUM IN WHICH THE OIL PHASE CONTAINS FROM 2 TO 8.5% FATTY ALCOHOLS AND FROM 5 TO 95% POLYBUTENE. THE DISPERSION PROVIDES FOR IMPROVED LUBRICATION PROPERTIES FOR HOT ROLLING AND IMPROVED SURFACE CHARACTERISTICS OF THE RESULTANT SHEET PRODUCTS.

3,770,636 DISPERSION FOR HOT ROLLING ALUMINUM PRODUCTS Ewell E. McDole, Danville, and Frank L. Howard, Livermore, Calif., assignors to Kaiser Aluminum & Chemical Corporation, Oakland, Calif. No Drawing. Filed Nov. 15, 1971, Ser. No. 198,898 Int. Cl. Cm 1/22, 3/10, 3/16 U.S. Cl. 252-495 11 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an oil-in-water dispersion for the hot rolling of aluminum in which the oil phase contains from 2 to 85% fatty alcohols and from 5 to 95% polybutene. The dispersion provides for improved lubrication properties for hot rolling and improved surface characteristics of the resultant sheet products.

BACKGROUND OF THE INVENTION This invention relates to an improved lubricating composition. More particularly, it relates to a dispersion of polybutene and fatty alcohols in water useful in the hot rolling of aluminum products.

In the normal fabrication of aluminum sheet and plate materials an ingot, at a temperature of from about 650 to 950 F., is passed through a breakdown mill to reduce the ingot to a thickness of about l-inch. After the breakdown passes the 1-inch thick plate is then rolled on a multi-stand mill or a reversing mill to a thickness of about 0.1-inch. The final temperature of the roduct of the rolling operation normally varies between about 500 and 700 F. During the rolling operation on the multi-stand mill, or the reversing mill, the workpiece and work rolls are normally flooded with a lubricant, uusally an oil-inwater emulsion. The primary functions of the oil-in-water emulsion are to reduce the friction, to prevent metalto-metal contact between the work rolls and the workpiece and to control the temperature of the work rolls.

One of the major problems encountered with the oil- United States Patent 0 "ice in-water emulsion is the small particles of aluminum and alloying elements which are removed from the surface of the workpiece and transferred to the working surfaces of the mill roll. The particles, which are highly oxidized, build up on the mill roll surface forming a coating thereon which is commonly termed roll coating. The particles of aluminum from the roll coating are subsequently re-transferred to and embedded in the surface of the workpiece. The embedded particles are commonly termed pickup. During the subsequent rolling operations these surface imperfections tend to be hidden and it is not until the sheet material is subsequently anodized that these imperfections again appear. The imperfections are sometimes noticeable after the etching step which is normally required prior to anodizing. The surface imperfections tend to be accentuated during the anodizing process, thus rendering the sheet product unsuitable for commercial use. By increasing the lubricity of the oil-in-water emulsion, the pickup deposition can be minimized. However, the lubrication properties of the oil-in-water emulsion must not be increased to the extent that the aluminum slab refuses to enter the mill rolls. Furthermore, if the friction between the workpiece and the mill rolls is reduced by an excessive amount, the workpiece tends to move laterally, or skid, in the mill which causes the prodnot to be misshapened.

In addition to the minimum lubrication and cooling characteristics, the lubricant must also meet other requirements before it has any commercial applicability. The lubricant must be capable of removing the residues of dehydrated oil from the surfaces of the work rolls and Patented Nov. 6, 1973 workpiece. Otherwise the residues Would accelerate roll coating formation and pickup. The mixture must also prevent rust and keep the coolant piping system clean.

The commercially available neat oil compositions employed to form an oil-in-water emulsion generally comprise a hydrocarbon oil, usually naphthenic in nature, a lubricity or wear reducing agent such as lauric acid, oleic acid, tricresyl phosphate, and the like, emulsifiers such as rosin and tall oil soaps and triethanolamine oleate, and frequently a coupling agent such as ethylene glycol to render the emulsifiers and lubricity agents soluble in the base oil. Frequently used neat oils include 591 Oil, sold by Texaco Inc., Prosol 4'6, sold by Mobil Oil Corporation and Tandemol K95A, sold by E. F. Houghton & Company. The oil phase of the emulsion generally comprises from 1 to 10% by weight of the emulsion. The emulsions prepared with the commercially available neat oils do provide sufficient lubrication and cooling during hot rolling, and compared with the previously used products, they significantly reduce the amount of pickup. However, the surface quality requirements for anodized sheet material have consistently increased over the years to a point where the pickup levels and the rejections therefrom are excessive when employing commercially available lubricants.

Against this background the present invention was developed.

DESCRIPTION OF THE INVENTION The present invention relates to an improved, non-staining lubricant composition which provides for a substantial reduction of pick-up and for a substantial improvement in the lubrication, cooling and other properties. Moreover, the lubricant provides for a simplified compositional control.

The composition of the present invention comprises from about 2 to preferably 5 to 50%, of a long chain fatty alcohol, or mixtures thereof, having from 8 to 20 carbon atoms, and from about 15 to preferably from 50 to 95%, polybutene. The polybutene, either straight or branch chain, must have a viscosity from about 50 to 70 SSU at F., preferably from 100 to 300 SSU at 100 F. Generally, two or more polybutenes are mixed to provide the polybutene with the desired viscosity level. Suitable commercially available polybutenes include Oronite 6, Oronite 8 and Oronite 128 sold by the Chevron Chemical Company. Most commercially available long chain aliphatic alcohols are mixtures of fatty alcohols such as Alfol 1216, manufactured by the Continental Oil Company, which is about 65% C12 alcohol, 23% C14 alcohol and 12% C16 alcohol.

In addition to the basic components, the lubricant of the present invention may also contain up to 5% emulsifiers, preferably anionic emulsifiers such as triethanolamine oleate, suitable corrosion inhibitors such as morpholinium oleate, in amounts up to 5%, and suitable antioxidants such as butylated hydroxytoluene (BHT), in amounts up to 1% In preparing the components as a lubricant for the hot rolling of aluminum products, preferably the polybutene and fatty alcohols are intimately mixed in a desired ratio, and the resultant neat oil is mixedwith water. The mixing is carried out to form an oil-water dispersion in which a substantial amount, preferably more than 30%, of the oil fraction exists as oil globules from 2 to 8 microns in size. An oil-water lubricant with a particle size predominantly below 2 microns in size, will not have sufficient lubricity for rolling purposes; whereas an oilwater lubricant having a particle size about 8 microns will have a lubricity which is too great for the hot rolling of aluminum, and the workpiece tends to refuse to enter the mill and to skid during rolling. The neat oil generally comprises from 1 to of the oil-Water dispersion or mixture. In the preferred embodiment of the present invention, the oil phase of the oil-water mixture is maintained in the proper particulate size by continually mechanically mixing the mixture. However, if desired, an emulsifier in amounts up to '5 of the neat oil, may be employed for emulsification and to maintain the proper size distribution of the oil phase. Preferably, the emulsifier is anionic because such emulsifiers allow the emulsion to be broken by adjusting the pH. It is preferred to mix these additives, such as emulsifiers, corrosion inhibitors and antioxidants, with the neat oil prior to mixing with water. Generally, the operating temperature of the dispersion is from about 100 to 160 F., preferably between 120 and 140 F.

The oil-in-water mixtures and emulsions of the present invention provide for a substantial reduction in the amount of pickup, greatly improved the surface brightness of the resultant sheet products, and substantially reduce the power requirements for a particular reduction in thickness.

To further illustrate the present invention, three oilin-water mixtures, or dispersions, were prepared in accordance with the present invention having the compositions described below for comparison with an oil-in-water emulsion containing 3.7% by weight of Prosol 46.

TABLE I [Lubricant composition] The polybutene was a blend of 48% Oronite polybutene No. 6 and 52% Oronite polybutene No. 8, the mixture having a viscosity of 275 SSU at 100 F. The fatty alcohol was Alfol 1216. The various components were blended into the desired proportions, then dispersed in water at a temperature of 120 F. by a model 8B Dispersonic sonolator, made by the Sonic Engineering Company. Test strips 3" wide by /8" thick of a 2024 alloy clad 2 /z% on each side with 1230 alloy were heated to a temperature of 800 F., then rolled with single pass reductions of 35%, 45%, 55% and 65% in a 2-high Schmitz mill, utilizing the above described lubricants in each of the reductions.

A comparison of these various lubricants is set forth below. The mill power is expressed as (mill amperes) and is interpolated to a 60% reduction. The specular reflectance measurements were taken by a Model D10 Hunter Goniophotometer at 45 incidence and the values expressed were taken in the longitudinal and transverse directions of the sheet. The amount of roll coating is expressed as milligrams of aluminum removed from the top roll by washing with aqueous caustic solution after 4 single pass reductions. The pick-up with the oil-inwater mixtures or dispersions of the present invention was not detectable by visual inspection; whereas, the pickup with Prosol 46 was objectionable.

TABLE II Transverse Lubricant No. Long The two and three component mixture of the neat oil of the present invention cons derably Simplifies the composition control as compared with the prior art compositions. Normally, the prior art compositions contain a base oil, lubricity agents, coupling agents, emulsifiers, wetting agents, and the like. Considerable efforts were necessary to maintain the composition limitations to maintain the oil-in-water emulsion operational. Furthermore, most emulsions needed long periods of time, for example, from two days to one week, for a break-in period, and during this break-in period no sheets of anodizable quality could be rolled. In the preferred embodiment the particle size of the oil globules is controlled to a large extent by the continual dispersion thereof, and therefore there is no need for a break-in period. Moreover, by simplifying the composition, the formation of degradation products is substantially mini mized.

The regeneration of prior art compositions contami nated with decomposition products and particulate has not been found practical because of the high capital costs involved for equipment for separating the oil phase from the aqueous phase, and because of the large number of ingredients which would have to be restored or adjusted in concentration. Normally, the contaminated emulsions are discarded. Because the mechanically dispersed composition of the preferred embodiment readily separated into an oil phase and water phase, regeneration of the lubricant is both practical and economical.

All percentages given herein are on a weight percent basis unless stated otherwise.

What is claimed is:

1. A non-staining hot rolling neat oil composition suitable for dispersion in water consisting essentially of from about 2 to of at least one saturated fatty alcohol having from 8 to 20 carbon atoms and from about 15 to 98% polybutene having a viscosity of from about 50 to 750 SSU at 100 F.

2. The neat oil of claim 1 containing an emulsifier in amounts up to 5%.

3. The neat oil of claim 1 containing from about 5 to 50% of at least one saturated fatty alcohol having from 8 to 20 carbon atoms and from 50 to polybutene having a viscosity of from about to 300 SSU at 100 F.

4. A non-staining lubricant for the hot rolling of aluminum products comprising an oil-in-water dispersion consisting essentially of an oil phase containing from about 5 to 50% of at least one saturated fatty alcohol having from 8 to 20 carbon atoms and from 50 to 95% polybutene having a viscosity of from about 100 to 300 SSU at 100 F. and an aqueous phase consisting essentially of water, the oil phase comprising from 1 to 30% of the dispersion.

5. The lubricant of claim 4 in which the oil phase contains up to 5% emulsifiers.

6. The lubricant of claim 4 in which at least 30% of the oil phase exists as particles between 2 and 8 microns in diameter.

7. In the process of hot rolling aluminum products, the improvement comprising contacting the aluminum Workpiece and Working roll surfaces with an oil-in-water dispersion consisting essentially of an oil phase containing from about 5 to 5 0% of at least one saturated fatty alcohol having from 8 to 20 carbon atoms and from 50 to 95 polybutene having a viscosity of from about 100 to 300 SSU at 100 F. and an aqueous phase consisting essentially of Water, the oil phase comprising from 1 to 30% of the dispersion.

8. The process of claim 7 in which at least 30% of the oil phase exists as particles between 2 and 8 microns in diameter.

9. The process of claim 7 wherein the oil phase of the oil-in-water mixture contains up to 5% corrosion inhibitors and up to 1% anti-oxidants.

10. The neat oil of claim 1 containing up to 5% corrosion inhibitors and up to 1% anti-oxidants.

5 11. The lubricant of claim 4 containing up to 5% corrosion inhibitors and up to 1% anti-oxidants.

References Cited UNITED STATES PATENTS 11/1968 'Treat 25249.5 9/1950 Hance et a1 25249.5 X 3/1972 Hotten 252-49.3

DANIEL E. WYMAN, Primary Examiner W. H. CANNON, Assistant Examiner US Cl. X.R.

Patent No. 3,770,636 Dated November 6, 1973 PHIN l hH'S RIM L lfiventofls) Ewell E. McDole and Frank L. Howard- It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, Line 43, "50 to 70 SSW should be --so to 750 ssU- Signed and sealed this 12th day of March l974.

(SEAL) Attes't:

EDWARD M.FLETCHER,JR. v C. MARSHALL DANN Attesting Officer I Commissioner of Patents FORM PO-1050 (10-69) -USCOMM-DC 60376-P69 If. r u.s. sovznunzur PRINTING ornc: \su o-ass-su, 

